Growing up, Roberto S. Luciani had subtle indications that his brain functioned differently from most people. For example, he couldn’t relate when others complained about a movie character not matching their mental image from the book. It wasn’t until his teenage years that everything fell into place. His mother had just woken up and was recounting a dream she had, describing it as 'movielike.' 'Up until then, I assumed that cartoon depictions of imagination were exaggerated,' Luciani recalls. 'I asked her what she meant and quickly realized my visual imagery was not functioning like hers.'
This realization led Luciani to discover he has a condition called aphantasia — an inability to visualize objects, people, and scenes in his mind. Growing up, this term didn’t even exist. Now, as a cognitive scientist at the University of Glasgow in Scotland, Luciani and other researchers are gaining a deeper understanding of how some brains operate, including those with a blind mind’s eye.
In a recent study, Luciani and his colleagues examined the connections between hearing and seeing. In most brains, these senses collaborate, with auditory information influencing visual brain areas. However, in people with aphantasia, this connection is weaker, as reported on November 4 in Current Biology. During brain scans, blindfolded participants listened to three sound scenes: a forest full of birds, a crowd of people, and a bustling street. In 10 people without aphantasia, these auditory scenes produced distinct neural patterns in the visual cortex. But in 23 people with aphantasia, these patterns were less pronounced.
Cognitive neuroscientist Lars Muckli, also from the University of Glasgow, highlights the diversity of brain organizations. 'Imagine the brain has an interconnectedness that varies in strength,' he says. At one end of the spectrum are people with synesthesia, where sounds and sights are tightly intertwined. 'In the midrange, you experience the mind’s eye — knowing something is not real, but sounds can trigger some images in your mind. And then you have aphantasia,' Muckli explains. 'Sounds don’t trigger any visual experience, not even a faint one.'
These findings not only explain the differences between the brains of people with and without aphantasia but also provide insights into brain function in general. 'The senses of the brain are more interconnected than our textbooks tell us,' Muckli notes. The results also raise philosophical questions about the various ways people perceive the world. Aphantasia 'exists in a realm of invisible differences between people that make our lived experiences unique, without us realizing,' Luciani says. 'I find it fascinating that there may be other differences lurking in the shadow of us assuming other people experience the world like us.'
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